A method of defrosting an energy recovery ventilator unit. The method comprises defrosting an energy recovery ventilator unit. The method comprises activating a defrost process of an enthalpy-exchange zone of the energy recovery ventilator unit when an air-flow blockage in the enthalpy-exchange zone coincides with a frost threshold in the ambient environment surrounding the energy recovery ventilator unit. The method also comprises terminating the defrost process when a heat transfer efficiency across the enthalpy-exchange zone returns to within 10 percent of a pre-frosting heat transfer efficiency wherein, the heat transfer efficiency is proportional to a temperature difference between an intake air zone of the energy recovery ventilator and a supply air zone of the energy recovery ventilator divided by a temperature difference between an return air zone of the energy recovery ventilator and the intake air zone.

In one embodiment, a system includes an inlet grid configured to reduce distortion of an incoming airflow. The system may also include a vibration device coupled to the inlet grid and a controller communicatively coupled to the vibration device. The controller may transmit a vibration signal to the vibration device causing the vibration device to vibrate the inlet grid such that the inlet grid resonates at a natural frequency inducing a mode shape in the inlet grid. The mode shape may break up and prevent ice on the inlet grid.

There is described a system and method for configuring, commissioning and troubleshooting an HVAC unit. A unit type configuration is established based on a type of HVAC system and temperature data, humidity data, and/or indoor air quality data. A fan configuration is established based on whether a variable frequency drive fan is identified. Cooling and heating stage configurations are established based on a compressor parameter and a heating stage parameter. An available auxiliary termination is identified in response to establishing the configurations. A safety is assigned to the available auxiliary termination in response to identifying the available auxiliary termination. An IO table is provided to an HVAC controller, which includes physical input/output assignments for the terminations of the HVAC controller based on the configurations and the assigned safety. For another embodiment, the fan configuration is established based on one of a traditional stage blower fan or variable frequency drive fan.

There is described a system and method for configuring, commissioning and troubleshooting an HVAC unit. A unit type configuration is established based on a type of HVAC system and temperature data, humidity data, and/or indoor air quality data. A fan configuration is established based on whether a variable frequency drive fan is identified. Cooling and heating stage configurations are established based on a compressor parameter and a heating stage parameter. An available auxiliary termination is identified in response to establishing the configurations. A safety is assigned to the available auxiliary termination in response to identifying the available auxiliary termination. An IO table is provided to an HVAC controller, which includes physical input/output assignments for the terminations of the HVAC controller based on the configurations and the assigned safety. For another embodiment, the fan configuration is established based on one of a traditional stage blower fan or variable frequency drive fan.

A heat exchange system and a method for determining whether flow of cooling medium passing through a heat exchanger is too low. The heat exchange system includes a refrigerant flow path in which refrigerant circulates; a cooling medium flow path in which cooling medium circulates; and a heat exchanger connected to both the refrigerant flow path and the cooling medium flow path so that the refrigerant and the cooling medium exchange heat in the heat exchanger. The heat exchange system includes a first temperature sensor arranged at a cooling medium inlet of the heat exchanger, a second temperature sensor at a cooling medium outlet of the heat exchanger, and a controller in communication with the first temperature sensor and the second temperature sensor. The controller is configured to determine whether the flow of cooling medium in the heat exchanger is too low based on a temperature difference.

A method of performing a defrost operation in a heating, ventilation and air conditioning (HVAC) system having a first heat exchanger and a second heat exchanger, the method including determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter; determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity.

A method of performing a defrost operation in a heating, ventilation and air conditioning (HVAC) system having a first heat exchanger and a second heat exchanger, the method including determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter; determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity.

According to one embodiment, an air conditioner includes an indoor unit, an outdoor unit, and a controller. The controller includes a first defrost module and a second defrost module. The first defrost module is configured to defrost a first outdoor heat exchanger and a second outdoor heat exchanger at the same time. The second defrost module is configured to start defrosting of the second outdoor heat exchanger in advance, and to perform defrosting of the first outdoor heat exchanger after the start of defrosting of the second outdoor heat exchanger.

A ventilation system including a ventilator and a processor. The ventilator includes a housing, first intake, second intake, first outlet, second outlet, dampers, first air blower, second air blower, total heat exchanger, and heat exchanger. The processor is configured to change the air flow path of air flowing through the housing from an intake flow path and discharge flow path while in a ventilation mode to a heat exchanger cleaning mode or a total heat exchanger drying mode, in which air in the room flows into the housing through the first outlet, passes through the heat exchanger and then the total heat exchanger, and is discharged to the space outside the room through the second outlet.

Air conditioner units and methods of operating the same are provided. A method of operating an air conditioner unit includes determining a fan speed as a function of a compressor speed of a variable speed compressor of the air conditioner unit. The method also includes activating a variable speed fan of the air conditioner unit at the fan speed. An air conditioner unit may include a controller, and the controller may be configured for performing the method.